Steaming — to 
180° — does a 
lot of good 
things to your 
soil. It cleans 
up disease or- 
ganisms, it kills 
soil-borne weed 
seeds, insects. 
Besides this, it 
tends to improve 
the physical con- 
dition. 
ths UD oh 
| os 
Oe 
We use the Thomas method (surface steaming) well de- 
scribed in a Cornell University Bulletin on the subject. Write 
the Dept. of Floriculture, Cornell University, Ithaca, New 
York. Soil must be heated to 180° for 30 minutes; on ground 
beds it should be heated to a depth of 8 inches to do a job. 
Some soils give “after sterilizing” troubles if planted immedi- 
ately after steaming. Symptoms: retarded, slowed, yellowish 
growth, poor roots. Cure: a very heavy, thoro leaching (or 
two). Turning the soil with forks helps. Some schools 
recommend 4-5 lbs. per 100 sq. ft. of gypsum before planting. 
It could do no harm, and may help the soil recover from the 
“steaming miseries.” Usually with a week or 10 days of 
leaching and waiting, you are safe. Some soils are OK the 
same day they are steamed. Actually, recent experience leads 
us to believe that it is less dangerous to bench cuttings imme- 
diately after steaming than to wait a week or two. Apparently, 
waiting 10 days allows time for the toxins to build up. 
Chemicals will kill soil insects, but are questionable in con- 
trol of diseases. 
_A word about excess salts: Every so often a grower com- 
plains of a gradual hardening and yellowing of his Mums— 
“just won’t grow” is the usual conclusion. A Solu-Bridge 
test in 20 minutes shows that there is a serious excess -of all 
salts in his soil. How did it get that way? Well, a very hard 
water can contribute large amounts of sulfates, carbonates, 
calcium. A too-heavy fertilizing program will cause build-up 
of nitrates, potash, etc. Some soils are naturally ‘saline’ — 
or loaded with salts. Some such soils can be cured by heavy 
and repeated leaching: others must be abandoned. 
Bench a Good Cutting 
Certainly good Mums can’t be grown unless the cutting 
used is grade A in every respect. They often aren't. Here 
are some points we find important: 
1. The cutting must be well rooted (roots an inch or so), 
but it must not be left in the sand too long. A week too long 
will harden and check it, and will surely give a slow starting 
plant. 
2. The cutting should be fat and succulent, not thin, hard 
and wiry. The first several batches from a bed of stock make 
the best ones. 
3. Cuttings must be free of disease and insects. Several 
important diseases are not apparent on the cutting. Good 
propagating ‘specialists carry out programs of culturing and 
isolating their stocks against such diseases. 
The great majority of growers today depend on such 
specialists for their cuttings. We recommend it. 
About Insects and Diseases 
As we see it, it’s more a question of setting up good routine 
control programs that will eliminate the common insect-disease 
troubles. It has been our experience that application every two 
weeks in summer, every month in winter, of a spray combining 
FT OF RS eS ames 
EFtO 2K 
ue 
WEST CHICAGO 
ILLINOIS 
Parathion and wettable sulfur with a spreader will eliminate 
most of the common Mum insect and disease problems. 
We have had to use Parathion aerosol bombs to combat 
thrip on open flowers several times this summer. A Parathion- 
water spray can be used on open flowers, but Aerosol seems 
faster, more effective, less apt to injure petals. 
Here are dilutions for the spray: 
Per 10 Gallons of Water 
24% ounces Parathion, 15% wettable powder. 
2 ounces fermate. 
3 ounces wettable sulfur powder 
plus spreader. 
The Parathion is the insecticide, and the most effective and 
versatile one we've ever used. It will give excellent control of 
the following pests if used regularly: red spider, aphis (green 
fly), midge, thrip, mealy bugs, tarnished plant bug, leaf tier, 
cut worm and leaf miner. It will also give excellent control 
of the leaf (foliar) nematode, since it penetrates the leaf 
tissue. It has a residual effect, making it effective for several 
days or more after spraying. 
The fermate is an excellent general fungicide. Mainly for 
Mums, it is aimed at leaf spot (septoria). 
Sulfur is particularly effective against mildew. 
This can be used without injury to Mums at any period 
except—crops showing color or with open flowers, better use 
Dithiono in aerosol bombs in such cases. 
Jobs the above spray won't do: 
1. Stunt: a virus that results in dwarfing to about half 
normal stem length and flower size, and yellowing of flowers 
on bronze and pink varieties. Foliage is slightly lighter, 
duller green. Stunted plants flower noticeably earlier than 
plants not affected. Control involves an extremely tedious 
selection and isolation process which is being carried out most 
carefully by the specialist-propagators. Once a plant is in- 
fected, there is no control. Typical stunt affects a relatively 
small percentage of a variety scattered at random thruout the 
bench. There is no drying or browning of foliage. 
2. Stem rot: rotting off of plants at the soil surface—quite 
similar to the stem rot of Stocks. It appears only during the 
hot part of summer. Steaming of soil helps. Shallow plant- 
ing of cuttings and keeping bench a little on the dry side till 
plants are established both help. Even during summer, a little 
“heat and air’ at night will help. Benching a few extras 
permits replacement of casualties. 
3. Petal spotting. Heat and air even during summer, espe- 
cially at night when humidity is high, will help a lot. Flowers 
must be kept dry as they open. Parzate spray applied to the 
flowers weekly from the time color shows helps—be sure 
flowers dry off from spraying before nightfall. Worst on 
standards and especially Mefo and Betsy Ross. When shad- 
ing during hot weather, drop sateen from 7 P.M. till 9 A.M. 
to avoid shading during afternoon heat. For more details, 
see GROWER TALKS, Sept. ’50, page 20. 
4. Verticillium (Seidewitz Disease). Causes browning, 
drying up of leaves. Main control: culturing of - cuttings, 
which is done by specialist propagators, and steaming soil. 
Also, when this or other foliage diseases threaten, avoid wet- 
ting foliage. 
Ed. Seidewitz, pink Mum, Yellow and White Shasta Pomps 
are among the more susceptible varieties. 
5. Dodder, There’s nothing quite so bad once it gets 
started! It is a pale green parasite-vine that grows all over 
and between Mum foliage and stems. It fastens itself securely 
to the plant and sucks the life from it. 
It is far cheaper to simply pull out and burn any infected 
plants. Do it promptly; it spreads very fast. 
A word on aerosol bombs. They will get most insects, and 
they're labor savers. For the smaller miscellaneous grower, 
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